[PATCH v3 0/4] Improve Hyper-V memory deposit error handling

[PATCH v3 0/4] Improve Hyper-V memory deposit error handling

[Stanislav Kinsburskii]

This series extends the MSHV driver to properly handle additional
memory-related error codes from the Microsoft Hypervisor by depositing
memory pages when needed.

Currently, when the hypervisor returns HV_STATUS_INSUFFICIENT_MEMORY
during partition creation, the driver calls hv_call_deposit_pages() to
provide the necessary memory. However, there are other memory-related
error codes that indicate the hypervisor needs additional memory
resources, but the driver does not attempt to deposit pages for these
cases.

This series introduces a dedicated helper function macro to identify all
memory-related error codes (HV_STATUS_INSUFFICIENT_MEMORY,
HV_STATUS_INSUFFICIENT_BUFFERS, HV_STATUS_INSUFFICIENT_DEVICE_DOMAINS, and
HV_STATUS_INSUFFICIENT_ROOT_MEMORY) and ensures the driver attempts to
deposit pages for all of them via new hv_deposit_memory() helper.

With these changes, partition creation becomes more robust by handling
all scenarios where the hypervisor requires additional memory deposits.

v3:
- Fix uninitialized num_pages variable in hv_deposit_memory_node() in case
  of HV_STATUS_INSUFFICIENT_ROOT_MEMORY status

v2:
- Rename hv_result_oom() into hv_result_needs_memory()

---

Stanislav Kinsburskii (4):
      mshv: Introduce hv_result_needs_memory() helper function
      mshv: Introduce hv_deposit_memory helper functions
      mshv: Handle insufficient contiguous memory hypervisor status
      mshv: Handle insufficient root memory hypervisor statuses


 drivers/hv/hv_common.c         |    3 ++
 drivers/hv/hv_proc.c           |   53 ++++++++++++++++++++++++++++++++++---
 drivers/hv/mshv_root_hv_call.c |   50 +++++++++++++++--------------------
 drivers/hv/mshv_root_main.c    |    5 +---
 include/asm-generic/mshyperv.h |   13 +++++++++
 include/hyperv/hvgdk_mini.h    |   57 +++++++++++++++++++++-------------------
 include/hyperv/hvhdk_mini.h    |    2 +
 7 files changed, 120 insertions(+), 63 deletions(-)

[PATCH v3 1/4] mshv: Introduce hv_result_needs_memory() helper function

[Stanislav Kinsburskii]

Replace direct comparisons of hv_result(status) against
HV_STATUS_INSUFFICIENT_MEMORY with a new hv_result_needs_memory() helper
function.
This improves code readability and provides a consistent and extendable
interface for checking out-of-memory conditions in hypercall results.

No functional changes intended.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
---
 drivers/hv/hv_proc.c           |   14 ++++++++++++--
 drivers/hv/mshv_root_hv_call.c |   25 ++++++++++++-------------
 drivers/hv/mshv_root_main.c    |    2 +-
 include/asm-generic/mshyperv.h |    3 +++
 4 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
index fbb4eb3901bb..e53204b9e05d 100644
--- a/drivers/hv/hv_proc.c
+++ b/drivers/hv/hv_proc.c
@@ -110,6 +110,16 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 }
 EXPORT_SYMBOL_GPL(hv_call_deposit_pages);
 
+bool hv_result_needs_memory(u64 status)
+{
+	switch (hv_result(status)) {
+	case HV_STATUS_INSUFFICIENT_MEMORY:
+		return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_result_needs_memory);
+
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 apic_id)
 {
 	struct hv_input_add_logical_processor *input;
@@ -137,7 +147,7 @@ int hv_call_add_logical_proc(int node, u32 lp_index, u32 apic_id)
 					 input, output);
 		local_irq_restore(flags);
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			if (!hv_result_success(status)) {
 				hv_status_err(status, "cpu %u apic ID: %u\n",
 					      lp_index, apic_id);
@@ -179,7 +189,7 @@ int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags)
 		status = hv_do_hypercall(HVCALL_CREATE_VP, input, NULL);
 		local_irq_restore(irq_flags);
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			if (!hv_result_success(status)) {
 				hv_status_err(status, "vcpu: %u, lp: %u\n",
 					      vp_index, flags);
diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c
index daee036e48bc..1c4a2dbf49c0 100644
--- a/drivers/hv/mshv_root_hv_call.c
+++ b/drivers/hv/mshv_root_hv_call.c
@@ -115,7 +115,7 @@ int hv_call_create_partition(u64 flags,
 		status = hv_do_hypercall(HVCALL_CREATE_PARTITION,
 					 input, output);
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			if (hv_result_success(status))
 				*partition_id = output->partition_id;
 			local_irq_restore(irq_flags);
@@ -147,7 +147,7 @@ int hv_call_initialize_partition(u64 partition_id)
 		status = hv_do_fast_hypercall8(HVCALL_INITIALIZE_PARTITION,
 					       *(u64 *)&input);
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			ret = hv_result_to_errno(status);
 			break;
 		}
@@ -239,7 +239,7 @@ static int hv_do_map_gpa_hcall(u64 partition_id, u64 gfn, u64 page_struct_count,
 
 		completed = hv_repcomp(status);
 
-		if (hv_result(status) == HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (hv_result_needs_memory(status)) {
 			ret = hv_call_deposit_pages(NUMA_NO_NODE, partition_id,
 						    HV_MAP_GPA_DEPOSIT_PAGES);
 			if (ret)
@@ -455,7 +455,7 @@ int hv_call_get_vp_state(u32 vp_index, u64 partition_id,
 
 		status = hv_do_hypercall(control, input, output);
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			if (hv_result_success(status) && ret_output)
 				memcpy(ret_output, output, sizeof(*output));
 
@@ -518,7 +518,7 @@ int hv_call_set_vp_state(u32 vp_index, u64 partition_id,
 
 		status = hv_do_hypercall(control, input, NULL);
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			local_irq_restore(flags);
 			ret = hv_result_to_errno(status);
 			break;
@@ -563,7 +563,7 @@ static int hv_call_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
 		status = hv_do_hypercall(HVCALL_MAP_VP_STATE_PAGE, input,
 					 output);
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			if (hv_result_success(status))
 				*state_page = pfn_to_page(output->map_location);
 			local_irq_restore(flags);
@@ -718,7 +718,7 @@ hv_call_create_port(u64 port_partition_id, union hv_port_id port_id,
 		if (hv_result_success(status))
 			break;
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			ret = hv_result_to_errno(status);
 			break;
 		}
@@ -772,7 +772,7 @@ hv_call_connect_port(u64 port_partition_id, union hv_port_id port_id,
 		if (hv_result_success(status))
 			break;
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			ret = hv_result_to_errno(status);
 			break;
 		}
@@ -850,7 +850,7 @@ static int hv_call_map_stats_page2(enum hv_stats_object_type type,
 		if (!ret)
 			break;
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			hv_status_debug(status, "\n");
 			break;
 		}
@@ -899,7 +899,7 @@ hv_call_map_stats_page(enum hv_stats_object_type type,
 	struct hv_input_map_stats_page *input;
 	struct hv_output_map_stats_page *output;
 	u64 status, pfn;
-	int hv_status, ret = 0;
+	int ret = 0;
 
 	do {
 		local_irq_save(flags);
@@ -915,13 +915,12 @@ hv_call_map_stats_page(enum hv_stats_object_type type,
 
 		local_irq_restore(flags);
 
-		hv_status = hv_result(status);
-		if (hv_status != HV_STATUS_INSUFFICIENT_MEMORY) {
+		if (!hv_result_needs_memory(status)) {
 			if (hv_result_success(status))
 				break;
 
 			if (hv_stats_get_area_type(type, identity) == HV_STATS_AREA_PARENT &&
-			    hv_status == HV_STATUS_INVALID_PARAMETER) {
+			    hv_result(status) == HV_STATUS_INVALID_PARAMETER) {
 				*addr = NULL;
 				return 0;
 			}
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index b429bb1fdffa..f5525651a565 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -251,7 +251,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
 		if (hv_result_success(status))
 			break;
 
-		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY)
+		if (!hv_result_needs_memory(status))
 			ret = hv_result_to_errno(status);
 		else
 			ret = hv_call_deposit_pages(NUMA_NO_NODE,
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index ecedab554c80..452426d5b2ab 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -342,6 +342,8 @@ static inline bool hv_parent_partition(void)
 {
 	return hv_root_partition() || hv_l1vh_partition();
 }
+
+bool hv_result_needs_memory(u64 status);
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
@@ -350,6 +352,7 @@ int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
 static inline bool hv_root_partition(void) { return false; }
 static inline bool hv_l1vh_partition(void) { return false; }
 static inline bool hv_parent_partition(void) { return false; }
+static inline bool hv_result_needs_memory(u64 status) { return false; }
 static inline int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 {
 	return -EOPNOTSUPP;

[PATCH v3 2/4] mshv: Introduce hv_deposit_memory helper functions

[Stanislav Kinsburskii]

Introduce hv_deposit_memory_node() and hv_deposit_memory() helper
functions to handle memory deposition with proper error handling.

The new hv_deposit_memory_node() function takes the hypervisor status
as a parameter and validates it before depositing pages. It checks for
HV_STATUS_INSUFFICIENT_MEMORY specifically and returns an error for
unexpected status codes.

This is a precursor patch to new out-of-memory error codes support.
No functional changes intended.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
---
 drivers/hv/hv_proc.c           |   21 +++++++++++++++++++--
 drivers/hv/mshv_root_hv_call.c |   25 +++++++++----------------
 drivers/hv/mshv_root_main.c    |    3 +--
 include/asm-generic/mshyperv.h |   10 ++++++++++
 4 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
index e53204b9e05d..53622e5886b8 100644
--- a/drivers/hv/hv_proc.c
+++ b/drivers/hv/hv_proc.c
@@ -110,6 +110,22 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 }
 EXPORT_SYMBOL_GPL(hv_call_deposit_pages);
 
+int hv_deposit_memory_node(int node, u64 partition_id,
+			   u64 hv_status)
+{
+	u32 num_pages = 1;
+
+	switch (hv_result(hv_status)) {
+	case HV_STATUS_INSUFFICIENT_MEMORY:
+		break;
+	default:
+		hv_status_err(hv_status, "Unexpected!\n");
+		return -ENOMEM;
+	}
+	return hv_call_deposit_pages(node, partition_id, num_pages);
+}
+EXPORT_SYMBOL_GPL(hv_deposit_memory_node);
+
 bool hv_result_needs_memory(u64 status)
 {
 	switch (hv_result(status)) {
@@ -155,7 +171,8 @@ int hv_call_add_logical_proc(int node, u32 lp_index, u32 apic_id)
 			}
 			break;
 		}
-		ret = hv_call_deposit_pages(node, hv_current_partition_id, 1);
+		ret = hv_deposit_memory_node(node, hv_current_partition_id,
+					     status);
 	} while (!ret);
 
 	return ret;
@@ -197,7 +214,7 @@ int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags)
 			}
 			break;
 		}
-		ret = hv_call_deposit_pages(node, partition_id, 1);
+		ret = hv_deposit_memory_node(node, partition_id, status);
 
 	} while (!ret);
 
diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c
index 1c4a2dbf49c0..7f91096f95a8 100644
--- a/drivers/hv/mshv_root_hv_call.c
+++ b/drivers/hv/mshv_root_hv_call.c
@@ -123,8 +123,7 @@ int hv_call_create_partition(u64 flags,
 			break;
 		}
 		local_irq_restore(irq_flags);
-		ret = hv_call_deposit_pages(NUMA_NO_NODE,
-					    hv_current_partition_id, 1);
+		ret = hv_deposit_memory(hv_current_partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -151,7 +150,7 @@ int hv_call_initialize_partition(u64 partition_id)
 			ret = hv_result_to_errno(status);
 			break;
 		}
-		ret = hv_call_deposit_pages(NUMA_NO_NODE, partition_id, 1);
+		ret = hv_deposit_memory(partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -465,8 +464,7 @@ int hv_call_get_vp_state(u32 vp_index, u64 partition_id,
 		}
 		local_irq_restore(flags);
 
-		ret = hv_call_deposit_pages(NUMA_NO_NODE,
-					    partition_id, 1);
+		ret = hv_deposit_memory(partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -525,8 +523,7 @@ int hv_call_set_vp_state(u32 vp_index, u64 partition_id,
 		}
 		local_irq_restore(flags);
 
-		ret = hv_call_deposit_pages(NUMA_NO_NODE,
-					    partition_id, 1);
+		ret = hv_deposit_memory(partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -573,7 +570,7 @@ static int hv_call_map_vp_state_page(u64 partition_id, u32 vp_index, u32 type,
 
 		local_irq_restore(flags);
 
-		ret = hv_call_deposit_pages(NUMA_NO_NODE, partition_id, 1);
+		ret = hv_deposit_memory(partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -722,8 +719,7 @@ hv_call_create_port(u64 port_partition_id, union hv_port_id port_id,
 			ret = hv_result_to_errno(status);
 			break;
 		}
-		ret = hv_call_deposit_pages(NUMA_NO_NODE, port_partition_id, 1);
-
+		ret = hv_deposit_memory(port_partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -776,8 +772,7 @@ hv_call_connect_port(u64 port_partition_id, union hv_port_id port_id,
 			ret = hv_result_to_errno(status);
 			break;
 		}
-		ret = hv_call_deposit_pages(NUMA_NO_NODE,
-					    connection_partition_id, 1);
+		ret = hv_deposit_memory(connection_partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -855,8 +850,7 @@ static int hv_call_map_stats_page2(enum hv_stats_object_type type,
 			break;
 		}
 
-		ret = hv_call_deposit_pages(NUMA_NO_NODE,
-					    hv_current_partition_id, 1);
+		ret = hv_deposit_memory(hv_current_partition_id, status);
 	} while (!ret);
 
 	return ret;
@@ -929,8 +923,7 @@ hv_call_map_stats_page(enum hv_stats_object_type type,
 			return hv_result_to_errno(status);
 		}
 
-		ret = hv_call_deposit_pages(NUMA_NO_NODE,
-					    hv_current_partition_id, 1);
+		ret = hv_deposit_memory(hv_current_partition_id, status);
 		if (ret)
 			return ret;
 	} while (!ret);
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index f5525651a565..cf58d9954638 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -254,8 +254,7 @@ static int mshv_ioctl_passthru_hvcall(struct mshv_partition *partition,
 		if (!hv_result_needs_memory(status))
 			ret = hv_result_to_errno(status);
 		else
-			ret = hv_call_deposit_pages(NUMA_NO_NODE,
-						    pt_id, 1);
+			ret = hv_deposit_memory(pt_id, status);
 	} while (!ret);
 
 	args.status = hv_result(status);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 452426d5b2ab..d37b68238c97 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -344,6 +344,7 @@ static inline bool hv_parent_partition(void)
 }
 
 bool hv_result_needs_memory(u64 status);
+int hv_deposit_memory_node(int node, u64 partition_id, u64 status);
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
@@ -353,6 +354,10 @@ static inline bool hv_root_partition(void) { return false; }
 static inline bool hv_l1vh_partition(void) { return false; }
 static inline bool hv_parent_partition(void) { return false; }
 static inline bool hv_result_needs_memory(u64 status) { return false; }
+static inline int hv_deposit_memory_node(int node, u64 partition_id, u64 status)
+{
+	return -EOPNOTSUPP;
+}
 static inline int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages)
 {
 	return -EOPNOTSUPP;
@@ -367,6 +372,11 @@ static inline int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u3
 }
 #endif /* CONFIG_MSHV_ROOT */
 
+static inline int hv_deposit_memory(u64 partition_id, u64 status)
+{
+	return hv_deposit_memory_node(NUMA_NO_NODE, partition_id, status);
+}
+
 #if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
 u8 __init get_vtl(void);
 #else

[PATCH v3 3/4] mshv: Handle insufficient contiguous memory hypervisor status

[Stanislav Kinsburskii]

The HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY status indicates that the
hypervisor lacks sufficient contiguous memory for its internal allocations.

When this status is encountered, allocate and deposit
HV_MAX_CONTIGUOUS_ALLOCATION_PAGES contiguous pages to the hypervisor.
HV_MAX_CONTIGUOUS_ALLOCATION_PAGES is defined in the hypervisor headers, a
deposit of this size will always satisfy the hypervisor's requirements.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
---
 drivers/hv/hv_common.c      |    1 +
 drivers/hv/hv_proc.c        |    4 ++++
 include/hyperv/hvgdk_mini.h |    1 +
 include/hyperv/hvhdk_mini.h |    2 ++
 4 files changed, 8 insertions(+)

diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index f1c17fb60dc1..f20596276662 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -793,6 +793,7 @@ static const struct hv_status_info hv_status_infos[] = {
 	_STATUS_INFO(HV_STATUS_UNKNOWN_PROPERTY,		-EIO),
 	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
 	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
+	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
 	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),
diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
index 53622e5886b8..181f6d02bce3 100644
--- a/drivers/hv/hv_proc.c
+++ b/drivers/hv/hv_proc.c
@@ -118,6 +118,9 @@ int hv_deposit_memory_node(int node, u64 partition_id,
 	switch (hv_result(hv_status)) {
 	case HV_STATUS_INSUFFICIENT_MEMORY:
 		break;
+	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
+		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
+		break;
 	default:
 		hv_status_err(hv_status, "Unexpected!\n");
 		return -ENOMEM;
@@ -130,6 +133,7 @@ bool hv_result_needs_memory(u64 status)
 {
 	switch (hv_result(status)) {
 	case HV_STATUS_INSUFFICIENT_MEMORY:
+	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
 		return true;
 	}
 	return false;
diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
index 30fbbde81c5c..99ea0d03e657 100644
--- a/include/hyperv/hvgdk_mini.h
+++ b/include/hyperv/hvgdk_mini.h
@@ -38,6 +38,7 @@ struct hv_u128 {
 #define HV_STATUS_INVALID_LP_INDEX		    0x41
 #define HV_STATUS_INVALID_REGISTER_VALUE	    0x50
 #define HV_STATUS_OPERATION_FAILED		    0x71
+#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY    0x75
 #define HV_STATUS_TIME_OUT			    0x78
 #define HV_STATUS_CALL_PENDING			    0x79
 #define HV_STATUS_VTL_ALREADY_ENABLED		    0x86
diff --git a/include/hyperv/hvhdk_mini.h b/include/hyperv/hvhdk_mini.h
index c0300910808b..091c03e26046 100644
--- a/include/hyperv/hvhdk_mini.h
+++ b/include/hyperv/hvhdk_mini.h
@@ -7,6 +7,8 @@
 
 #include "hvgdk_mini.h"
 
+#define HV_MAX_CONTIGUOUS_ALLOCATION_PAGES	8
+
 /*
  * Doorbell connection_info flags.
  */

[PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses

[Stanislav Kinsburskii]

When creating guest partition objects, the hypervisor may fail to
allocate root partition pages and return an insufficient memory status.
In this case, deposit memory using the root partition ID instead.

Note: This error should never occur in a guest of L1VH partition context.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
---
 drivers/hv/hv_common.c      |    2 +
 drivers/hv/hv_proc.c        |   14 ++++++++++
 include/hyperv/hvgdk_mini.h |   58 ++++++++++++++++++++++---------------------
 3 files changed, 46 insertions(+), 28 deletions(-)

diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index f20596276662..6b67ac616789 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -794,6 +794,8 @@ static const struct hv_status_info hv_status_infos[] = {
 	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
 	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
 	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
+	_STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY,	-ENOMEM),
+	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY,	-ENOMEM),
 	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),
diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
index 181f6d02bce3..5f4fd9c3231c 100644
--- a/drivers/hv/hv_proc.c
+++ b/drivers/hv/hv_proc.c
@@ -121,6 +121,18 @@ int hv_deposit_memory_node(int node, u64 partition_id,
 	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
 		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
 		break;
+
+	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
+		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
+		fallthrough;
+	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
+		if (!hv_root_partition()) {
+			hv_status_err(hv_status, "Unexpected root memory deposit\n");
+			return -ENOMEM;
+		}
+		partition_id = HV_PARTITION_ID_SELF;
+		break;
+
 	default:
 		hv_status_err(hv_status, "Unexpected!\n");
 		return -ENOMEM;
@@ -134,6 +146,8 @@ bool hv_result_needs_memory(u64 status)
 	switch (hv_result(status)) {
 	case HV_STATUS_INSUFFICIENT_MEMORY:
 	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
+	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
+	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
 		return true;
 	}
 	return false;
diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
index 99ea0d03e657..50f5a1419052 100644
--- a/include/hyperv/hvgdk_mini.h
+++ b/include/hyperv/hvgdk_mini.h
@@ -14,34 +14,36 @@ struct hv_u128 {
 } __packed;
 
 /* NOTE: when adding below, update hv_result_to_string() */
-#define HV_STATUS_SUCCESS			    0x0
-#define HV_STATUS_INVALID_HYPERCALL_CODE	    0x2
-#define HV_STATUS_INVALID_HYPERCALL_INPUT	    0x3
-#define HV_STATUS_INVALID_ALIGNMENT		    0x4
-#define HV_STATUS_INVALID_PARAMETER		    0x5
-#define HV_STATUS_ACCESS_DENIED			    0x6
-#define HV_STATUS_INVALID_PARTITION_STATE	    0x7
-#define HV_STATUS_OPERATION_DENIED		    0x8
-#define HV_STATUS_UNKNOWN_PROPERTY		    0x9
-#define HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE	    0xA
-#define HV_STATUS_INSUFFICIENT_MEMORY		    0xB
-#define HV_STATUS_INVALID_PARTITION_ID		    0xD
-#define HV_STATUS_INVALID_VP_INDEX		    0xE
-#define HV_STATUS_NOT_FOUND			    0x10
-#define HV_STATUS_INVALID_PORT_ID		    0x11
-#define HV_STATUS_INVALID_CONNECTION_ID		    0x12
-#define HV_STATUS_INSUFFICIENT_BUFFERS		    0x13
-#define HV_STATUS_NOT_ACKNOWLEDGED		    0x14
-#define HV_STATUS_INVALID_VP_STATE		    0x15
-#define HV_STATUS_NO_RESOURCES			    0x1D
-#define HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED   0x20
-#define HV_STATUS_INVALID_LP_INDEX		    0x41
-#define HV_STATUS_INVALID_REGISTER_VALUE	    0x50
-#define HV_STATUS_OPERATION_FAILED		    0x71
-#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY    0x75
-#define HV_STATUS_TIME_OUT			    0x78
-#define HV_STATUS_CALL_PENDING			    0x79
-#define HV_STATUS_VTL_ALREADY_ENABLED		    0x86
+#define HV_STATUS_SUCCESS				0x0
+#define HV_STATUS_INVALID_HYPERCALL_CODE		0x2
+#define HV_STATUS_INVALID_HYPERCALL_INPUT		0x3
+#define HV_STATUS_INVALID_ALIGNMENT			0x4
+#define HV_STATUS_INVALID_PARAMETER			0x5
+#define HV_STATUS_ACCESS_DENIED				0x6
+#define HV_STATUS_INVALID_PARTITION_STATE		0x7
+#define HV_STATUS_OPERATION_DENIED			0x8
+#define HV_STATUS_UNKNOWN_PROPERTY			0x9
+#define HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE		0xA
+#define HV_STATUS_INSUFFICIENT_MEMORY			0xB
+#define HV_STATUS_INVALID_PARTITION_ID			0xD
+#define HV_STATUS_INVALID_VP_INDEX			0xE
+#define HV_STATUS_NOT_FOUND				0x10
+#define HV_STATUS_INVALID_PORT_ID			0x11
+#define HV_STATUS_INVALID_CONNECTION_ID			0x12
+#define HV_STATUS_INSUFFICIENT_BUFFERS			0x13
+#define HV_STATUS_NOT_ACKNOWLEDGED			0x14
+#define HV_STATUS_INVALID_VP_STATE			0x15
+#define HV_STATUS_NO_RESOURCES				0x1D
+#define HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED	0x20
+#define HV_STATUS_INVALID_LP_INDEX			0x41
+#define HV_STATUS_INVALID_REGISTER_VALUE		0x50
+#define HV_STATUS_OPERATION_FAILED			0x71
+#define HV_STATUS_INSUFFICIENT_ROOT_MEMORY		0x73
+#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY	0x75
+#define HV_STATUS_TIME_OUT				0x78
+#define HV_STATUS_CALL_PENDING				0x79
+#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY	0x83
+#define HV_STATUS_VTL_ALREADY_ENABLED			0x86
 
 /*
  * The Hyper-V TimeRefCount register and the TSC

Re: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses

[Anirudh Rayabharam]

On Thu, Feb 05, 2026 at 06:42:27PM +0000, Stanislav Kinsburskii wrote:
> When creating guest partition objects, the hypervisor may fail to
> allocate root partition pages and return an insufficient memory status.
> In this case, deposit memory using the root partition ID instead.
> 
> Note: This error should never occur in a guest of L1VH partition context.

I think you should rephrse this to:

"... should never occur in an L1VH partition"

because none of the errors in this patch series occur inside a guest. They
either occur in L1VH or root or both.

> 
> Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
> ---
>  drivers/hv/hv_common.c      |    2 +
>  drivers/hv/hv_proc.c        |   14 ++++++++++
>  include/hyperv/hvgdk_mini.h |   58 ++++++++++++++++++++++---------------------
>  3 files changed, 46 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index f20596276662..6b67ac616789 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -794,6 +794,8 @@ static const struct hv_status_info hv_status_infos[] = {
>  	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
>  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
>  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
> +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY,	-ENOMEM),
> +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY,	-ENOMEM),
>  	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID,		-EINVAL),
>  	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
>  	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),
> diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
> index 181f6d02bce3..5f4fd9c3231c 100644
> --- a/drivers/hv/hv_proc.c
> +++ b/drivers/hv/hv_proc.c
> @@ -121,6 +121,18 @@ int hv_deposit_memory_node(int node, u64 partition_id,
>  	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
>  		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
>  		break;
> +
> +	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
> +		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> +		fallthrough;
> +	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:

I have the same comment as on v2 about num_pages being uninitialized when we
reach this case directly.

Thanks,
Anirudh.

> +		if (!hv_root_partition()) {
> +			hv_status_err(hv_status, "Unexpected root memory deposit\n");
> +			return -ENOMEM;
> +		}
> +		partition_id = HV_PARTITION_ID_SELF;
> +		break;
> +
>  	default:
>  		hv_status_err(hv_status, "Unexpected!\n");
>  		return -ENOMEM;
> @@ -134,6 +146,8 @@ bool hv_result_needs_memory(u64 status)
>  	switch (hv_result(status)) {
>  	case HV_STATUS_INSUFFICIENT_MEMORY:
>  	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
> +	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
> +	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
>  		return true;
>  	}
>  	return false;
> diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
> index 99ea0d03e657..50f5a1419052 100644
> --- a/include/hyperv/hvgdk_mini.h
> +++ b/include/hyperv/hvgdk_mini.h
> @@ -14,34 +14,36 @@ struct hv_u128 {
>  } __packed;
>  
>  /* NOTE: when adding below, update hv_result_to_string() */
> -#define HV_STATUS_SUCCESS			    0x0
> -#define HV_STATUS_INVALID_HYPERCALL_CODE	    0x2
> -#define HV_STATUS_INVALID_HYPERCALL_INPUT	    0x3
> -#define HV_STATUS_INVALID_ALIGNMENT		    0x4
> -#define HV_STATUS_INVALID_PARAMETER		    0x5
> -#define HV_STATUS_ACCESS_DENIED			    0x6
> -#define HV_STATUS_INVALID_PARTITION_STATE	    0x7
> -#define HV_STATUS_OPERATION_DENIED		    0x8
> -#define HV_STATUS_UNKNOWN_PROPERTY		    0x9
> -#define HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE	    0xA
> -#define HV_STATUS_INSUFFICIENT_MEMORY		    0xB
> -#define HV_STATUS_INVALID_PARTITION_ID		    0xD
> -#define HV_STATUS_INVALID_VP_INDEX		    0xE
> -#define HV_STATUS_NOT_FOUND			    0x10
> -#define HV_STATUS_INVALID_PORT_ID		    0x11
> -#define HV_STATUS_INVALID_CONNECTION_ID		    0x12
> -#define HV_STATUS_INSUFFICIENT_BUFFERS		    0x13
> -#define HV_STATUS_NOT_ACKNOWLEDGED		    0x14
> -#define HV_STATUS_INVALID_VP_STATE		    0x15
> -#define HV_STATUS_NO_RESOURCES			    0x1D
> -#define HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED   0x20
> -#define HV_STATUS_INVALID_LP_INDEX		    0x41
> -#define HV_STATUS_INVALID_REGISTER_VALUE	    0x50
> -#define HV_STATUS_OPERATION_FAILED		    0x71
> -#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY    0x75
> -#define HV_STATUS_TIME_OUT			    0x78
> -#define HV_STATUS_CALL_PENDING			    0x79
> -#define HV_STATUS_VTL_ALREADY_ENABLED		    0x86
> +#define HV_STATUS_SUCCESS				0x0
> +#define HV_STATUS_INVALID_HYPERCALL_CODE		0x2
> +#define HV_STATUS_INVALID_HYPERCALL_INPUT		0x3
> +#define HV_STATUS_INVALID_ALIGNMENT			0x4
> +#define HV_STATUS_INVALID_PARAMETER			0x5
> +#define HV_STATUS_ACCESS_DENIED				0x6
> +#define HV_STATUS_INVALID_PARTITION_STATE		0x7
> +#define HV_STATUS_OPERATION_DENIED			0x8
> +#define HV_STATUS_UNKNOWN_PROPERTY			0x9
> +#define HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE		0xA
> +#define HV_STATUS_INSUFFICIENT_MEMORY			0xB
> +#define HV_STATUS_INVALID_PARTITION_ID			0xD
> +#define HV_STATUS_INVALID_VP_INDEX			0xE
> +#define HV_STATUS_NOT_FOUND				0x10
> +#define HV_STATUS_INVALID_PORT_ID			0x11
> +#define HV_STATUS_INVALID_CONNECTION_ID			0x12
> +#define HV_STATUS_INSUFFICIENT_BUFFERS			0x13
> +#define HV_STATUS_NOT_ACKNOWLEDGED			0x14
> +#define HV_STATUS_INVALID_VP_STATE			0x15
> +#define HV_STATUS_NO_RESOURCES				0x1D
> +#define HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED	0x20
> +#define HV_STATUS_INVALID_LP_INDEX			0x41
> +#define HV_STATUS_INVALID_REGISTER_VALUE		0x50
> +#define HV_STATUS_OPERATION_FAILED			0x71
> +#define HV_STATUS_INSUFFICIENT_ROOT_MEMORY		0x73
> +#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY	0x75
> +#define HV_STATUS_TIME_OUT				0x78
> +#define HV_STATUS_CALL_PENDING				0x79
> +#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY	0x83
> +#define HV_STATUS_VTL_ALREADY_ENABLED			0x86
>  
>  /*
>   * The Hyper-V TimeRefCount register and the TSC
> 
> 

Re: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses

[Stanislav Kinsburskii]

On Fri, Feb 06, 2026 at 05:56:41AM +0000, Anirudh Rayabharam wrote:
> On Thu, Feb 05, 2026 at 06:42:27PM +0000, Stanislav Kinsburskii wrote:
> > When creating guest partition objects, the hypervisor may fail to
> > allocate root partition pages and return an insufficient memory status.
> > In this case, deposit memory using the root partition ID instead.
> > 
> > Note: This error should never occur in a guest of L1VH partition context.
> 
> I think you should rephrse this to:
> 
> "... should never occur in an L1VH partition"
> 
> because none of the errors in this patch series occur inside a guest. They
> either occur in L1VH or root or both.
> 
> > 
> > Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
> > ---
> >  drivers/hv/hv_common.c      |    2 +
> >  drivers/hv/hv_proc.c        |   14 ++++++++++
> >  include/hyperv/hvgdk_mini.h |   58 ++++++++++++++++++++++---------------------
> >  3 files changed, 46 insertions(+), 28 deletions(-)
> > 
> > diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> > index f20596276662..6b67ac616789 100644
> > --- a/drivers/hv/hv_common.c
> > +++ b/drivers/hv/hv_common.c
> > @@ -794,6 +794,8 @@ static const struct hv_status_info hv_status_infos[] = {
> >  	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
> >  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
> >  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
> > +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY,	-ENOMEM),
> > +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY,	-ENOMEM),
> >  	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID,		-EINVAL),
> >  	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
> >  	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),
> > diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
> > index 181f6d02bce3..5f4fd9c3231c 100644
> > --- a/drivers/hv/hv_proc.c
> > +++ b/drivers/hv/hv_proc.c
> > @@ -121,6 +121,18 @@ int hv_deposit_memory_node(int node, u64 partition_id,
> >  	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
> >  		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> >  		break;
> > +
> > +	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
> > +		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> > +		fallthrough;
> > +	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
> 
> I have the same comment as on v2 about num_pages being uninitialized when we
> reach this case directly.
> 

It is initialized to 1 on top of the function.

Thanks,
Stanislav.

> Thanks,
> Anirudh.
> 
> > +		if (!hv_root_partition()) {
> > +			hv_status_err(hv_status, "Unexpected root memory deposit\n");
> > +			return -ENOMEM;
> > +		}
> > +		partition_id = HV_PARTITION_ID_SELF;
> > +		break;
> > +
> >  	default:
> >  		hv_status_err(hv_status, "Unexpected!\n");
> >  		return -ENOMEM;
> > @@ -134,6 +146,8 @@ bool hv_result_needs_memory(u64 status)
> >  	switch (hv_result(status)) {
> >  	case HV_STATUS_INSUFFICIENT_MEMORY:
> >  	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
> > +	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
> > +	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
> >  		return true;
> >  	}
> >  	return false;
> > diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
> > index 99ea0d03e657..50f5a1419052 100644
> > --- a/include/hyperv/hvgdk_mini.h
> > +++ b/include/hyperv/hvgdk_mini.h
> > @@ -14,34 +14,36 @@ struct hv_u128 {
> >  } __packed;
> >  
> >  /* NOTE: when adding below, update hv_result_to_string() */
> > -#define HV_STATUS_SUCCESS			    0x0
> > -#define HV_STATUS_INVALID_HYPERCALL_CODE	    0x2
> > -#define HV_STATUS_INVALID_HYPERCALL_INPUT	    0x3
> > -#define HV_STATUS_INVALID_ALIGNMENT		    0x4
> > -#define HV_STATUS_INVALID_PARAMETER		    0x5
> > -#define HV_STATUS_ACCESS_DENIED			    0x6
> > -#define HV_STATUS_INVALID_PARTITION_STATE	    0x7
> > -#define HV_STATUS_OPERATION_DENIED		    0x8
> > -#define HV_STATUS_UNKNOWN_PROPERTY		    0x9
> > -#define HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE	    0xA
> > -#define HV_STATUS_INSUFFICIENT_MEMORY		    0xB
> > -#define HV_STATUS_INVALID_PARTITION_ID		    0xD
> > -#define HV_STATUS_INVALID_VP_INDEX		    0xE
> > -#define HV_STATUS_NOT_FOUND			    0x10
> > -#define HV_STATUS_INVALID_PORT_ID		    0x11
> > -#define HV_STATUS_INVALID_CONNECTION_ID		    0x12
> > -#define HV_STATUS_INSUFFICIENT_BUFFERS		    0x13
> > -#define HV_STATUS_NOT_ACKNOWLEDGED		    0x14
> > -#define HV_STATUS_INVALID_VP_STATE		    0x15
> > -#define HV_STATUS_NO_RESOURCES			    0x1D
> > -#define HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED   0x20
> > -#define HV_STATUS_INVALID_LP_INDEX		    0x41
> > -#define HV_STATUS_INVALID_REGISTER_VALUE	    0x50
> > -#define HV_STATUS_OPERATION_FAILED		    0x71
> > -#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY    0x75
> > -#define HV_STATUS_TIME_OUT			    0x78
> > -#define HV_STATUS_CALL_PENDING			    0x79
> > -#define HV_STATUS_VTL_ALREADY_ENABLED		    0x86
> > +#define HV_STATUS_SUCCESS				0x0
> > +#define HV_STATUS_INVALID_HYPERCALL_CODE		0x2
> > +#define HV_STATUS_INVALID_HYPERCALL_INPUT		0x3
> > +#define HV_STATUS_INVALID_ALIGNMENT			0x4
> > +#define HV_STATUS_INVALID_PARAMETER			0x5
> > +#define HV_STATUS_ACCESS_DENIED				0x6
> > +#define HV_STATUS_INVALID_PARTITION_STATE		0x7
> > +#define HV_STATUS_OPERATION_DENIED			0x8
> > +#define HV_STATUS_UNKNOWN_PROPERTY			0x9
> > +#define HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE		0xA
> > +#define HV_STATUS_INSUFFICIENT_MEMORY			0xB
> > +#define HV_STATUS_INVALID_PARTITION_ID			0xD
> > +#define HV_STATUS_INVALID_VP_INDEX			0xE
> > +#define HV_STATUS_NOT_FOUND				0x10
> > +#define HV_STATUS_INVALID_PORT_ID			0x11
> > +#define HV_STATUS_INVALID_CONNECTION_ID			0x12
> > +#define HV_STATUS_INSUFFICIENT_BUFFERS			0x13
> > +#define HV_STATUS_NOT_ACKNOWLEDGED			0x14
> > +#define HV_STATUS_INVALID_VP_STATE			0x15
> > +#define HV_STATUS_NO_RESOURCES				0x1D
> > +#define HV_STATUS_PROCESSOR_FEATURE_NOT_SUPPORTED	0x20
> > +#define HV_STATUS_INVALID_LP_INDEX			0x41
> > +#define HV_STATUS_INVALID_REGISTER_VALUE		0x50
> > +#define HV_STATUS_OPERATION_FAILED			0x71
> > +#define HV_STATUS_INSUFFICIENT_ROOT_MEMORY		0x73
> > +#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY	0x75
> > +#define HV_STATUS_TIME_OUT				0x78
> > +#define HV_STATUS_CALL_PENDING				0x79
> > +#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY	0x83
> > +#define HV_STATUS_VTL_ALREADY_ENABLED			0x86
> >  
> >  /*
> >   * The Hyper-V TimeRefCount register and the TSC
> > 
> > 

RE: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses

[Michael Kelley]

From: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com> Sent: Thursday, February 5, 2026 10:42 AM
> To: kys@microsoft.com; haiyangz@microsoft.com; wei.liu@kernel.org;
> decui@microsoft.com; longli@microsoft.com
> Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses
> 
> When creating guest partition objects, the hypervisor may fail to
> allocate root partition pages and return an insufficient memory status.
> In this case, deposit memory using the root partition ID instead.
> 
> Note: This error should never occur in a guest of L1VH partition context.
> 
> Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
> ---
>  drivers/hv/hv_common.c      |    2 +
>  drivers/hv/hv_proc.c        |   14 ++++++++++
>  include/hyperv/hvgdk_mini.h |   58 ++++++++++++++++++++++---------------------
>  3 files changed, 46 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index f20596276662..6b67ac616789 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -794,6 +794,8 @@ static const struct hv_status_info hv_status_infos[] = {
>  	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
>  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
>  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
> +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY,	-ENOMEM),
> +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY, 	-ENOMEM),
>  	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID,		-EINVAL),
>  	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
>  	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),
> diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
> index 181f6d02bce3..5f4fd9c3231c 100644
> --- a/drivers/hv/hv_proc.c
> +++ b/drivers/hv/hv_proc.c
> @@ -121,6 +121,18 @@ int hv_deposit_memory_node(int node, u64 partition_id,
>  	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
>  		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
>  		break;
> +
> +	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
> +		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> +		fallthrough;
> +	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
> +		if (!hv_root_partition()) {
> +			hv_status_err(hv_status, "Unexpected root memory deposit\n");
> +			return -ENOMEM;
> +		}
> +		partition_id = HV_PARTITION_ID_SELF;
> +		break;
> +

Per the discussion in v1 of this patch set, if the number of pages that should be
deposited in a particular situation is different from what this function provides,
the fallback is to use hv_call_deposit_pages() directly. From what I see, there's
only one such fallback case after a hypercall failure -- in hv_do_map_gpa_hcall().
The other uses of hv_call_deposit_pages() are initial deposits when creating a
VP or partition.

But if hv_call_deposit_pages() is used directly, the logic added here to detect
insufficient root memory and deposit to HV_PARTITION_ID_SELF isn't applied.
So if the hypercall in hv_do_map_gpa_hcall() fails with insufficient root
memory, the deposit is done to the wrong partition ID. If that case can
actually happen, then some additional logic is needed in
hv_do_map_gpa_hcall() to handle it. Or there needs to be a fallback
function that contains the logic.

Other than that, everything else in this patch set looks good to me.

Michael

>  	default:
>  		hv_status_err(hv_status, "Unexpected!\n");
>  		return -ENOMEM;

Re: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses

[Wei Liu]

On Fri, Feb 06, 2026 at 05:56:41AM +0000, Anirudh Rayabharam wrote:
> On Thu, Feb 05, 2026 at 06:42:27PM +0000, Stanislav Kinsburskii wrote:
> > When creating guest partition objects, the hypervisor may fail to
> > allocate root partition pages and return an insufficient memory status.
> > In this case, deposit memory using the root partition ID instead.
> > 
> > Note: This error should never occur in a guest of L1VH partition context.
> 
> I think you should rephrse this to:
> 
> "... should never occur in an L1VH partition"
> 
> because none of the errors in this patch series occur inside a guest. They
> either occur in L1VH or root or both.

I have dropped this note from the commit message. If anything, this
should be in the code so that it can be kept up to date.

Wei

Re: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses

[Wei Liu]

On Fri, Feb 06, 2026 at 06:54:55PM +0000, Michael Kelley wrote:
> From: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com> Sent: Thursday, February 5, 2026 10:42 AM
> > To: kys@microsoft.com; haiyangz@microsoft.com; wei.liu@kernel.org;
> > decui@microsoft.com; longli@microsoft.com
> > Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org
> > Subject: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses
> > 
> > When creating guest partition objects, the hypervisor may fail to
> > allocate root partition pages and return an insufficient memory status.
> > In this case, deposit memory using the root partition ID instead.
> > 
> > Note: This error should never occur in a guest of L1VH partition context.
> > 
> > Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
> > ---
> >  drivers/hv/hv_common.c      |    2 +
> >  drivers/hv/hv_proc.c        |   14 ++++++++++
> >  include/hyperv/hvgdk_mini.h |   58 ++++++++++++++++++++++---------------------
> >  3 files changed, 46 insertions(+), 28 deletions(-)
> > 
> > diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> > index f20596276662..6b67ac616789 100644
> > --- a/drivers/hv/hv_common.c
> > +++ b/drivers/hv/hv_common.c
> > @@ -794,6 +794,8 @@ static const struct hv_status_info hv_status_infos[] = {
> >  	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
> >  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
> >  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
> > +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY,	-ENOMEM),
> > +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY, 	-ENOMEM),
> >  	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID,		-EINVAL),
> >  	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
> >  	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),
> > diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
> > index 181f6d02bce3..5f4fd9c3231c 100644
> > --- a/drivers/hv/hv_proc.c
> > +++ b/drivers/hv/hv_proc.c
> > @@ -121,6 +121,18 @@ int hv_deposit_memory_node(int node, u64 partition_id,
> >  	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
> >  		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> >  		break;
> > +
> > +	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
> > +		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> > +		fallthrough;
> > +	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
> > +		if (!hv_root_partition()) {
> > +			hv_status_err(hv_status, "Unexpected root memory deposit\n");
> > +			return -ENOMEM;
> > +		}
> > +		partition_id = HV_PARTITION_ID_SELF;
> > +		break;
> > +
> 
> Per the discussion in v1 of this patch set, if the number of pages that should be
> deposited in a particular situation is different from what this function provides,
> the fallback is to use hv_call_deposit_pages() directly. From what I see, there's
> only one such fallback case after a hypercall failure -- in hv_do_map_gpa_hcall().
> The other uses of hv_call_deposit_pages() are initial deposits when creating a
> VP or partition.
> 
> But if hv_call_deposit_pages() is used directly, the logic added here to detect
> insufficient root memory and deposit to HV_PARTITION_ID_SELF isn't applied.
> So if the hypercall in hv_do_map_gpa_hcall() fails with insufficient root
> memory, the deposit is done to the wrong partition ID. If that case can
> actually happen, then some additional logic is needed in
> hv_do_map_gpa_hcall() to handle it. Or there needs to be a fallback
> function that contains the logic.

Stanislav, how about this comment? Please submit a follow-up patch if
necessary.

Wei

> 
> Other than that, everything else in this patch set looks good to me.
> 
> Michael
> 
> >  	default:
> >  		hv_status_err(hv_status, "Unexpected!\n");
> >  		return -ENOMEM;

Re: [PATCH v3 0/4] Improve Hyper-V memory deposit error handling

[Wei Liu]

On Thu, Feb 05, 2026 at 06:42:04PM +0000, Stanislav Kinsburskii wrote:
> This series extends the MSHV driver to properly handle additional
> memory-related error codes from the Microsoft Hypervisor by depositing
> memory pages when needed.
> 
> Currently, when the hypervisor returns HV_STATUS_INSUFFICIENT_MEMORY
> during partition creation, the driver calls hv_call_deposit_pages() to
> provide the necessary memory. However, there are other memory-related
> error codes that indicate the hypervisor needs additional memory
> resources, but the driver does not attempt to deposit pages for these
> cases.
> 
> This series introduces a dedicated helper function macro to identify all
> memory-related error codes (HV_STATUS_INSUFFICIENT_MEMORY,
> HV_STATUS_INSUFFICIENT_BUFFERS, HV_STATUS_INSUFFICIENT_DEVICE_DOMAINS, and
> HV_STATUS_INSUFFICIENT_ROOT_MEMORY) and ensures the driver attempts to
> deposit pages for all of them via new hv_deposit_memory() helper.
> 
> With these changes, partition creation becomes more robust by handling
> all scenarios where the hypervisor requires additional memory deposits.
> 
> v3:
> - Fix uninitialized num_pages variable in hv_deposit_memory_node() in case
>   of HV_STATUS_INSUFFICIENT_ROOT_MEMORY status
> 

I fixed a typo pointed out by Mukesh in the previous version, dropped
the note from the commit message in the last patch, and applied this to
hyperv-next.

Please address Michael's comment in patch four and send out a follow-up
patch if necessary.

Wei

Re: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses

[Stanislav Kinsburskii]

On Thu, Feb 19, 2026 at 06:47:01AM +0000, Wei Liu wrote:
> On Fri, Feb 06, 2026 at 06:54:55PM +0000, Michael Kelley wrote:
> > From: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com> Sent: Thursday, February 5, 2026 10:42 AM
> > > To: kys@microsoft.com; haiyangz@microsoft.com; wei.liu@kernel.org;
> > > decui@microsoft.com; longli@microsoft.com
> > > Cc: linux-hyperv@vger.kernel.org; linux-kernel@vger.kernel.org
> > > Subject: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor statuses
> > > 
> > > When creating guest partition objects, the hypervisor may fail to
> > > allocate root partition pages and return an insufficient memory status.
> > > In this case, deposit memory using the root partition ID instead.
> > > 
> > > Note: This error should never occur in a guest of L1VH partition context.
> > > 
> > > Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
> > > ---
> > >  drivers/hv/hv_common.c      |    2 +
> > >  drivers/hv/hv_proc.c        |   14 ++++++++++
> > >  include/hyperv/hvgdk_mini.h |   58 ++++++++++++++++++++++---------------------
> > >  3 files changed, 46 insertions(+), 28 deletions(-)
> > > 
> > > diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> > > index f20596276662..6b67ac616789 100644
> > > --- a/drivers/hv/hv_common.c
> > > +++ b/drivers/hv/hv_common.c
> > > @@ -794,6 +794,8 @@ static const struct hv_status_info hv_status_infos[] = {
> > >  	_STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE,	-EIO),
> > >  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY,		-ENOMEM),
> > >  	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY,	-ENOMEM),
> > > +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY,	-ENOMEM),
> > > +	_STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY, 	-ENOMEM),
> > >  	_STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID,		-EINVAL),
> > >  	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
> > >  	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),
> > > diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c
> > > index 181f6d02bce3..5f4fd9c3231c 100644
> > > --- a/drivers/hv/hv_proc.c
> > > +++ b/drivers/hv/hv_proc.c
> > > @@ -121,6 +121,18 @@ int hv_deposit_memory_node(int node, u64 partition_id,
> > >  	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
> > >  		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> > >  		break;
> > > +
> > > +	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY:
> > > +		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
> > > +		fallthrough;
> > > +	case HV_STATUS_INSUFFICIENT_ROOT_MEMORY:
> > > +		if (!hv_root_partition()) {
> > > +			hv_status_err(hv_status, "Unexpected root memory deposit\n");
> > > +			return -ENOMEM;
> > > +		}
> > > +		partition_id = HV_PARTITION_ID_SELF;
> > > +		break;
> > > +
> > 
> > Per the discussion in v1 of this patch set, if the number of pages that should be
> > deposited in a particular situation is different from what this function provides,
> > the fallback is to use hv_call_deposit_pages() directly. From what I see, there's
> > only one such fallback case after a hypercall failure -- in hv_do_map_gpa_hcall().
> > The other uses of hv_call_deposit_pages() are initial deposits when creating a
> > VP or partition.
> > 
> > But if hv_call_deposit_pages() is used directly, the logic added here to detect
> > insufficient root memory and deposit to HV_PARTITION_ID_SELF isn't applied.
> > So if the hypercall in hv_do_map_gpa_hcall() fails with insufficient root
> > memory, the deposit is done to the wrong partition ID. If that case can
> > actually happen, then some additional logic is needed in
> > hv_do_map_gpa_hcall() to handle it. Or there needs to be a fallback
> > function that contains the logic.
> 
> Stanislav, how about this comment? Please submit a follow-up patch if
> necessary.
> 

I'll sumbit a follow-up patch.

Thanks,
Stanislav

> Wei
> 
> > 
> > Other than that, everything else in this patch set looks good to me.
> > 
> > Michael
> > 
> > >  	default:
> > >  		hv_status_err(hv_status, "Unexpected!\n");
> > >  		return -ENOMEM;